title: Synthesis and magnetothermal properties of a ferromagnetically coupled Ni(II)-Gd(III)-Ni(II) cluster.
abstract: A linear trimeric cluster of molecular formula [Ni2Gd(L(-))6](NO3) (1) (L(-) = (C14H12NO2) has been isolated with its structure determined via single crystal X-ray diffraction. Magnetic susceptibility measurements of 1 show that the nickel and gadolinium ions are coupled ferromagnetically, with a ground total spin state (S) of 11/2. Best fit spin Hamiltonian parameters obtained for 1 are J(1(Ni-Gd)) = +0.54 cm(-1), g = 2.01. EPR measurements confirm a low magnetic anisotropy (D = -0.135 cm(-1)) for 1. Heat capacity determination of the magnetocaloric effect (MCE) parameters for 1 shows that the change in magnetic entropy (-ΔS(m)) achieves a maximum of 13.74 J kg(-1) K(-1) at 4.0 K, with the ferromagnetic coupling giving a rapid change in low applied fields, confirming the potential of Gd molecular derivatives as coolants at liquid helium temperature.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra 400076, India. eswar@chem.iitb.ac.in.
authors.forename: Apoorva
authors.initials: A
authors.lastname: Upadhyay
authors.forename: Navatha
authors.initials: N
authors.lastname: Komatireddy
authors.forename: Alberto
authors.initials: A
authors.lastname: Ghirri
authors.forename: Floriana
authors.initials: F
authors.lastname: Tuna
authors.forename: Stuart K
authors.initials: SK
authors.lastname: Langley
authors.forename: Anant K
authors.initials: AK
authors.lastname: Srivastava
authors.forename: E Carolina
authors.initials: EC
authors.lastname: Sañudo
authors.forename: Boujemaa
authors.initials: B
authors.lastname: Moubaraki
authors.forename: Keith S
authors.initials: KS
authors.lastname: Murray
authors.forename: Eric J L
authors.initials: EJ
authors.lastname: McInnes
authors.forename: Marco
authors.initials: M
authors.lastname: Affronte
authors.forename: Maheswaran
authors.initials: M
authors.lastname: Shanmugam